A grand jury has reached a decision on whether to indict Darren Wilson, the white Ferguson, Mo., police officer whose fatal shooting of an unarmed black teenager sparked days of turbulent protests, sources close to the process said.

News conferences are being prepared by the county prosecutor’s office and the Missouri governor, sources said. Those news conferences will likely come later Monday.

The sources gave no indication of whether Wilson, 28, will face state charges in the August shooting death of 18-year-old Michael Brown, which triggered a frank conversation about race and police interaction with African Americans.

The grand jury’s decision is the latest turn in a case marked in the national consciousness by the stunning images of protesters looting stores and police wearing riot gear and deploying tear gas in the days after Brown’s death. Details of the grand jury’s deliberations have leaked out in recent weeks, angering the Brown family and protesters who saw it as a signal that no charges would be filed.

Although a parallel federal civil rights investigation of the shooting is continuing, federal investigators have all but concluded that they do not have a case against Wilson, law enforcement officials have said. Federal investigators are also conducting a broader probe of the Ferguson Police Department.

If Wilson is not charged, government officials are bracing for protests in the St. Louis area and nationwide. They have discussed emergency plans in the event of a violent reaction, while protest and community leaders have mapped out their response in hopes of avoiding the unrest that exploded after Brown was killed.

Chico Harlan contributed to this report.

Memorable images from Ferguson

The protests in Ferguson, Mo., have produced images reminiscent of war zones abroad and of the civil-rights era clashes.

A protester takes shelter from tear-gas vapors billowing around him on Aug. 13 in Ferguson, Mo. Police used tear gas on a crowd that was protesting teenager Michael Brown’s death.David Carson/St. Louis Post-Dispatch via AP